Arithmetic operator

2, 1 variable

A variable defines an equal sign (=) to assign a value to the variable

= The left side is the variable name

= The right-hand side is the value of the variable name = value

Money = weight * price print (money)Copy the code

Note: A variable name defines a variable only when it first appears

2, 2 Variable type

Integer, floating point, Boolean, complex, non-numeric, string, list, primitive, dictionary

Type ## You can view the type of a function.Copy the code

2, 3 Calculation between different types of variables

1) Numerical variables can be calculated directly

In: I = 10 f = 10.5b = True print(I *f) print(I *b) print(f*b) out: 105.0 10 10.5Copy the code

Note: In Boolean type True corresponds to 1, False corresponds to 0

2)”+” concatenation string

In: first_name = 'three' last_name = 'liu' print(first_name + last_name) out: threeCopy the code

3) String variables and integers repeatedly concatenate the same string using *

In :print(' 3 '* 10) print(' 3' * 10Copy the code

2, 4 variable input (using codes to get user input through the keyboard)

1) Get from the input function

String variable = input(" prompt ") ## Anything the user enters is considered a string by PythonCopy the code

Note: function, a pre-prepared function, can be used directly without worrying about internal code details

2) Type conversion function

Int (x) ## Converts x to an integer float (x) ## converts x to a floating point numberCopy the code

3) Buy apples

# input apple price = input(' please input apple price: \n') ## convert to float: price = input(' please input apple price: \n') ## Input apple weight = input(' please input apple price: \n') ## input apple weight = input(' please input apple price: \n') ## input apple weight = input(' please input apple price: \n') ## \n') ## convert directly to float: weight = float(input(' please input apple weight: Price = float(price) weight_f = float(weight) price_f = float(weight) + str(money))Copy the code

2, 5 formatted output of variables

%s — string

%d — a signed decimal integer. %06d represents a 6-digit integer preceded by 0

%f – floating point number

%% — prints %

Format:

Print (' format string '% 1) print(' format string' % 2.....)Copy the code

case

Price = float(input(' please input apple price: \n')) weight = float(input(' please input apple weight: \n') \n') ## print(' %(price,weight,money) ') ## print(' %(price,weight,money) ') ## print(' %(price,weight,money)Copy the code